Clinical orthodontists frequently face the difficulty of moving teeth into narrowed atrophic alveolar ridges resulting from early loss of a tooth or rapid resorption of the ridge following tooth extraction. Recent reports suggest that bone grafting techniques may be useful in augmenting alveolar ridges and maintaining ridge width. This study is designed to establish the use of the cat as the animal model to evaluate a synthetic resorbable bone grafting material. The suitability of the material, Synthograft, will be evaluated to test the application of established bone grafting techniques to enhance orthodontic movement of teeth into edentulous spaces. Twelve adult cats will be used to simulate this orthodontic situation. Mandibular first premolars and maxillary second premolars will be extracted under surgical anesthesia, and teeth will be prepared to accept orthodontic appliances. A resorbable synthetic bone graft will be placed in one mandibular extraction site, and all extraction sites will be sutured closed. Cats will undergo a 6-week healing period to allow healing, new bone growth, resorption, and alveolar ridge remodeling. Following this, cats will be sedated every three weeks from 12 weeks to permit all subsequent experimental manipulations. These will consist of tooth cleanings, placement or reactivation of orthodontic appliances to move mandibular premolars into the edentulous spaces, and measuring tooth movement. At the end of the 12-week period, cats will be sacrificed. Block resections will be made of the mandible containing the graft sites and orthodontically-treated teeth. Specimens will be prepared for histologic study of root resorption. Clinical results of tooth movement and root resorption will be evaluated to determine the promise of using Synthograft to study bone grafting techniques for orthodontic purposes in future studies. Biostatistical support will be used for assistance with study design, sample sizing and statistical analysis of the results.